Primary Sinus Surgery - PDF

44 44 Primary Sinus Surgery Devyani Lal, James A. Stankiewicz KEY POINTS...

44 44 Primary Sinus Surgery Devyani Lal, James A. Stankiewicz KEY POINTS unique to the patient. Surgery must only be undertaken after a thorough review of patient expectations, surgical anatomy, and Primary surgery for chronic rhinosinusitis is almost endoscopic review of the nasal and sinus pathology, and, generally, exclusively performed endoscopically. after failure of appropriate medical therapy. Functional endoscopic sinus surgery (FESS) aims to restore mucociliary function by reestablishing ANATOMY physiologic sinus ventilation and drainage. Identification of anatomic landmarks and recognition of variations Surgery should be personalized. The extent of surgery are imperative to maximize benefits and limit complications from depends on symptoms and the pathology. ESS.11 This chapter offers a concise review of the relevant endo- “Large” hole surgery may be employed in certain scopic surgical anatomy.12-24 The surgeon must also be familiar disease states to optimize topical drug delivery. with external landmarks and with the three-dimensional spatial orientation. Standardized nomenclature based on the recommenda- Identification of anatomic landmarks and variations tions of the Anatomic Terminology Group at the International helps limit complications. Conference on Sinus Disease12 and the recent European Position Major complications of endoscopic sinus surgery (ESS) Paper on the Anatomical Terminology of the Internal Nose and include cerebrospinal fluid leak, blindness, diplopia, Paranasal Sinuses are used in this chapter.13 internal carotid artery injury, and death. ESS provides significant improvement in overall and Ostiomeatal Complex disease-specific quality of life. The OMC (Fig. 44.1) is a functional concept rather than an Common causes of failure of ESS include lateralized anatomic structure with defined boundaries. It represents the final middle turbinate, failure to incorporate maxillary ostium common pathway for drainage and ventilation of the ethmoidal, in the middle meatal antrostomy, maxillary ostium maxillary, and frontal sinuses. Although the OMC’s exact boundaries stenosis, frontal recess scarring, residual ethmoidal air are not defined, it comprises structures bound between the medial cells, and adhesions. orbital wall and the middle turbinate. The OMC comprises the uncinate process, ethmoidal infundibulum, hiatus semilunaris, anterior ethmoidal cells, and the ostia of the anterior ethmoidal, maxillary, and frontal sinuses (see Fig. 44.1). The uncinate process is the first structure encountered in the middle meatus when the middle turbinate is medialized. It is a BACKGROUND sickle-shaped bone that runs anterosuperior to posteroinferior, A surgical approach to the maxillary sinus through its anterior with fibrous and bony attachments along the lateral nasal wall. It wall was described in 1675 by Molinetti.1 In the 1890s, Caldwell, lies in the sagittal plane and forms the medial wall of the ethmoidal Spicer, and Luc1,2 added an additional opening into the sinus infundibulum. The ethmoidal infundibulum is a funnel-shaped through the inferior meatus. The Caldwell-Luc procedures formed three-dimensional space between the uncinate process medially the primary surgical treatment of choice for chronic rhinosinusitis and the lamina papyracea laterally, into which the anterior sinuses (CRS) through the early twentieth century. Although Hirschmann3 drain. The maxillary sinus opens into the inferior aspect of the conducted the first endoscopic examination of the nose with a ethmoidal infundibulum at a 45-degree angle, and the frontal modified cystoscope in 1901, the modern era of endoscopic sinus sinus may drain into its superior part. The inferior semilunar surgery (ESS) evolved with the development of Hopkins rods in hiatus, commonly referred to as the hiatus semilunaris, is a two- the 1950s. Messerklinger4 pioneered the study of the endoscopic dimensional slit that lies between the free edge of the uncinate anatomy and pathophysiology of the paranasal sinuses and published process and the ethmoidal bulla. It is a cleft that connects the his experience with ESS in 1978.4-6 He highlighted the role of middle meatus into the infundibulum laterally. The infundibulum the ostiomeatal complex (OMC) in the pathophysiology of rhi- is surgically accessed from the nose by a probe passed through nosinusitis and directed attention to it during surgery. His then the hiatus semilunaris. resident, Stammberger,5-9 was instrumental in popularizing this The superior attachment of the uncinate process has implications technique outside Germany and Austria,3 although Kennedy10 is on the drainage of the frontal sinuses. The uncinate process may credited with the introduction of ESS to the United States in attach either to the lamina papyracea, the skull base, or the middle 1985.3 With widespread availability of endoscopes and instrumenta- turbinate (Fig. 44.2). When the uncinate attaches to the skull base tion and with focused training in endoscopic techniques, primary or middle turbinate, the frontal sinus drains into the superior surgery for CRS is now almost exclusively performed endoscopically. aspect of the infundibulum. However, more commonly, the uncinate External and intranasal nonendoscopic approaches have limited process attaches laterally to the orbit below the internal frontal indications in primary ESS. Endoscopic techniques are now ostium, forming a terminal recess (recessus terminalis). In this case, routinely being applied to the management of many non- the frontal sinus drains medial to the uncinate process into the inflammatory sinonasal disorders. The decision to operate and middle meatus and not into the ethmoidal infundibulum. The the extent of surgery are dictated by the patient’s symptoms and uncinate may actually have multiple attachments to the orbit, the pathophysiology of the disease process. Surgery should, middle turbinate, and skull base; the above statements are meant therefore, should be personalized and tailored to address disease to simplify understanding how frontal recess drainage may be 677 Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 677.e1 Abstract Keywords 44 Primary surgery for chronic rhinosinusitis is almost exclusively Endoscopic sinus surgery performed endoscopically. Functional endoscopic sinus surgery sinus surgery (FESS) aims to restore mucociliary function. Surgery should always ethmoidectomy be performed systematically following a preformed plan. Early maxillary antrostomy identification of anatomic landmarks helps optimize success and frontal sinusotomy limit complications. The natural ostia of maxillary, sphenoid, and sphenoidotomy frontal sinus should be identified prior to ostioplasty on these complications sinuses. A thorough and meticulous dissection of ethmoidal parti- rhinosinusitis tions is critical to successful ethmoidectomy as well as successful chronic rhinosinusitis maxillary, sphenoid, and frontal surgery. The middle turbinate nasal polyposis must be thoughtfully addressed at the conclusion of sinus surgery. middle turbinate Common causes of failure of endoscopic sinus surgery (ESS) include lateralized middle turbinate, missed middle meatal antrostomy, maxillary ostium stenosis, frontal recess scarring, residual ethmoidal air cells, residual ethmoidal partitions along the skull base and lamina papyracea (“central ethmoidectomy”), missed sphenoid ostium, and middle meatal adhesions. Major complications of ESS include cerebrospinal fluid leak, blindness, diplopia, internal carotid artery injury, and death. The surgeon must be technically proficient in addressing the anatomy and disease relevant to executing the planned surgery and have access to the necessary instrumentation. ESS provides significant improvement in overall and disease-specific quality of life. Surgery should be personalized to adequately address the patient’s symptoms and disease to optimize success and limit complications. “Large-hole” sinus surgery may be indicated for some sinus pathologies to help optimize topical drug delivery. Thorough ethmoidectomy with removal of all ethmoidal partitions is most critical in these patients. Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 678 PART IV Sinus, Rhinology, and Allergy/Immunology HS LP BE U MT BE U M A MT I U BE MT B C Fig. 44.1 Left ostiomeatal complex (enclosed by blue circle) is bound laterally by the medial orbital wall or lamina papyracea (LP) and medially by the middle turbinate (MT). BE, bulla ethmoidalis; U, uncinate process. (A) Coronal CT section outlining ostiomeatal complex boundaries. (B) Endoscopic view of left nasal cavity with the middle turbinate being medialized. (C) Closer view of the left middle meatus. The uncinate process extends anteriorly to the anterior maxillary line (M). Its posterior free margin parallels the ethmoidal bulla. The hiatus semilunaris (HS, white arrows) is a two-dimensional cleft between the posterior free edge of the uncinate and the ethmoidal bulla. It is the gap through which the nasal cavity communicates with the ethmoidal infundibulum (I). The infundibulum (black arrow) is a three-dimensional space between the uncinate process and lamina papyracea. This endoscopic figure shows the maxillary ball probe being passed through the linear hiatus semilunaris into the infundibulum. A B C Fig. 44.2 Coronal schematic view of the ostiomeatal complex showing the superior attachments of the uncinate process to the lamina papyracea (A), the roof of the ethmoidal complex (B), or the middle turbinate (C). If the uncinate process attaches to the roof of the ethmoid or to the middle turbinate, the frontal sinus drains into the infundibulum. If the uncinate attaches to the lamina papyracea, the frontal sinus drains medially, next to the middle turbinate. affected by these uncinate attachments. The uncinate process must Middle Turbinate be removed to gain access to the anterior ethmoidal sinuses, the maxillary sinus, and the frontal recess. Its posteroinferior portion The middle turbinate (MT) is a boomerang-shaped structure (Fig. overlies the maxillary sinus ostium and must be removed to identify 44.3). The MT basal lamella is the entire MT attachment to the natural maxillary ostium. the lateral nasal wall and skull base. The MT basal lamella can Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 679 44 1 1. Anterior (vertical) attachment U to agger nasi and cribriform plate BE 4 3 2. Middle (coronal/oblique) attachment to lamina papyracea 4. Free anterior edge 3. Posterior (horizontal/axial) attachment to maxilla, palatine bone, orbit Fig. 44.3 Schematic view of the right middle turbinate viewed from the lateral aspect illustrates the anterior vertical (1), middle oblique (2), and posterior horizontal (3) attachments. Inset, endoscopic views of the right middle turbinate show the free anterior edge (4) and the anterior (1) and posterior (3) attachments. U, uncinate; BE, bulla ethmoidalis. FS MT2 ANC PE Anterior B MT2 SS MT IT MT Fig. 44.4 The oblique, second part of the middle turbinate (MT2) attaches to the lamina papyracea via the basal lamella, separating the anterior ethmoidal (B) from the posterior ethmoidal (PE) cells. This part lies in a coronal/frontal plane and is best viewed on a sagittal view computed tomography scan. ANC, agger nasi cell; FS, Frontal sinus; IT, inferior turbinate; MT, middle turbinate; SS, sphenoid sinus. be conveniently thought of in three parts from the anterior to turbinate. If the vertical or horizontal attachment is injured, the posterior aspects. The part that is first encountered during nasal MT will lateralize and scar down the middle meatus and posterior endoscopy is the vertical part, which attaches to the agger nasi ethmoidal complex. region anteriorly and then to the cribriform plate superiorly. This part is oriented in the sagittal plane. The second part has an oblique orientation in the coronal plane, which attaches to the medial Ethmoidal Complex orbital wall. The third and most posterior part, often referred to The ethmoidal complex is divided by the oblique part of the MT as the horizontal basal lamella, is its posterior buttress, lying in basal lamella into the anterior and posterior ethmoidal cells (Fig. the axial plane and attaching to the lateral nasal wall at the lamina 44.4). Any cell that drains into the middle meatus is considered papyracea, maxilla, and perpendicular process of palatine bone. an anterior ethmoidal cell, and those that open into the superior The oblique part of the basal lamella is the only part of the MT meatus are posterior ethmoidal cells. There are no middle ethmoidal that can be sacrificed without compromising the integrity of the cells. Sometimes, ethmoidal cells pneumatize toward adjacent Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 680 PART IV Sinus, Rhinology, and Allergy/Immunology sinuses and impact their drainage, extending into the maxillary cells and one of the most constant, occurring in 98.5% of computed sinus (infraorbital or Haller cell), frontal recess (frontoethmoidal tomography (CT) scans.20 The ANCs have a close relationship and supraorbital cells), and the sphenoid sinus (sphenoethmoidal with the nasolacrimal drainage system, lying just posterior to the or Onodi cell). superior aspect of the nasolacrimal duct and the lacrimal sac. On The ethmoidal bulla is an anterior ethmoidal cell, and it is endoscopy, the cell appears as a projection of the lateral nasal wall the largest and most prominent cell of the ethmoid complex. anterior to, or at the attachment of, the middle turbinate. The It is the first cell encountered posterior to the uncinate process ANC is key in frontal sinus surgery.20-24 It may pneumatize so far during entry into the anterior ethmoidal complex. Frequently, superiorly into the frontal sinus as to be mistaken for the sinus the ethmoidal bulla has a bony attachment to the skull base, the itself when viewed endoscopically from below. A common mistake bulla lamella. The lateral wall of the ethmoidal bulla is the medial is to remove the floor and posterior cell wall, leaving the cap or wall of the orbit, and it drains into the suprabullar or retrobullar dome of the cell lying in the frontal recess. Likewise, a partially recess (sinus lateralis; the combination of the suprabullar and resected ethmoidal bulla lamella can also scar the frontal recess retrobullar recess). The suprabullar recess and the retrobullar leading to iatrogenic frontal sinus obstruction. recess are clefts, rather than cells, bordered superiorly by the The infraorbital ethmoidal cell (IOC), previously called the ethmoidal roof, laterally by the lamina papyracea, inferiorly by Haller cell, is an anterior ethmoidal cell that pneumatizes into the the roof of the ethmoidal bulla, and posteriorly by the basal orbital floor above the maxillary sinus ostium (see Fig. 44.5B) and lamella. The superior hiatus semilunaris, or hiatus secondarius, is may compromise its patency. When this cell’s common wall with the two-dimensional space that connects the middle meatus into the maxillary sinus ostium is not adequately resected, edema may these recesses. develop, obstructing the maxillary sinus ostium. The lateral wall The agger nasi is a bony mound on the ethmoid situated at of the IOC may be attached to the infraorbital nerve canal and the attachment of the middle turbinate to the lateral nasal wall. must, therefore, be removed carefully. Anterior ethmoidal cells in When the agger nasi is pneumatized, it forms the agger nasi cell relationship to the frontal recess may impact its drainage and are (ANC; Fig. 44.5A). The ANC is the most anterior of all ethmoidal discussed in detail with the frontal sinus anatomy. SEC ANC IOC SS MO SEC ANC IOC ON MO ICA AO MT SS A B C Fig. 44.5 Ethmoidal cells. Top row shows computed tomography (CT) scan with corresponding endoscopic view below. (A) The agger nasi cell (ANC) is the most anterior cell seen on a coronal CT scan and anterior to the middle turbinate (MT). Endoscopically it is seen as a bulge on the middle turbinate attachment and may narrow the superior ethmoidal infundibulum. (B) Coronal CT section shows bilateral infraorbital ethmoidal cell (IOC, Haller cell) narrowing the inferior ethmoidal infundibulum and attaching laterally to the infraorbital canal. The maxillary sinus opens into the inferior part of the infundibulum at a 45-degree angle. Endoscopic view of the left infundibulum after uncinectomy shows the infraorbital ethmoidal cell narrowing the inferior infundibulum and potentially obstructing drainage of the natural maxillary ostium (MO). The natural maxillary ostium is elliptically shaped and opens into the floor of the infundibulum at a 45-degree angle, not directly into the lateral wall. Accessory ostia (AO) are usually circular and are present here in the posterior fontanelle. (C) The sphenoethmoidal cell (SEC), or Onodi cell, is a posterior ethmoidal cell that is lateral and superior to the sphenoid sinus (SS), which is usually smaller, pushed medially and inferiorly. The figures show arrows pointing to a left SEC on coronal and sagittal CT cuts. The endoscopic image demonstrates the relationship of the SEC to the SS and shows the optic nerve (ON) and internal carotid artery (ICA) lying in relation to the SEC lateral wall. Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 681 44 ST Septum ST SER MT MT, v A Septum SO MT Septum ST Choana B C Fig. 44.6 Endoscopic transnasal view of the right superior turbinate (ST) and superior meatus, showing progressively closer posterior views in (A) through (C). Anteriorly, the superior turbinate shares a skull base attachment with the middle turbinate (MT) and runs in a sagittal plane like the middle turbinate. The superior meatus (small arrow in B) is, therefore, posterior to the medial half of the middle portion of the basal lamella of the middle turbinate. Posterior ethmoidal cells open into the superior meatus. Inferiorly, the superior turbinate forms the lateral wall of the sphenoethmoidal recess (SER, large arrow in B), which lies between the septum medially and the superior meatus laterally. The sphenoid ostium (SO) opens into the sphenoethmoidal recess. MT,v, middle turbinate, vertical part. The posterior ethmoidal complex consists of one to five cells maxillary sinus ostium opens into the inferior aspect of the that drain into the superior or the supreme meatus (Figs. 44.6 infundibulum, it can only be visualized on nasal endoscopy if and 44.7). When highly pneumatized, the posterior ethmoidal the uncinate bone has been resected in that area. Openings in the cells may extend above the orbit (supraorbital ethmoidal [SOE] medial maxillary wall that are visible in the presence of an intact cell) and above the sphenoid sinus. The sphenoethmoidal cell uncinate process are likely to be accessory ostia opening through (SEC [Onodi cell]) is a posterior ethmoidal cell that pneumatizes the anterior or posterior fontanelle area. Not incorporating the superior and lateral to the sphenoid sinus. The sphenoid sinus true maxillary sinus ostium into the surgical antrostomy remains lies inferomedial to the most posterior ethmoidal cell, including the most common cause of failure of a maxillary antrostomy. the SEC (Onodi cell) (see Fig. 44.5). Both the internal carotid artery (ICA) and the optic nerve can be exposed within the SEC (see Fig. 44.5C). Sphenoid Sinus The sphenoid sinus (Fig. 44.8) is the most posterior paranasal sinus. Its natural ostium opens into the sphenoethmoidal recess Maxillary Sinus (SER). This recess lies medial and posterior to the superior tur- The natural ostium of the maxillary sinus (see Fig. 44.5B) drains binate, anterior to the anterior wall of the sphenoid, and medial into the inferior aspect of the ethmoidal infundibulum at a to the nasal septum. Therefore, the sphenoid sinus natural ostium 45-degree angle, and it is found just below the orbital floor in the is consistently medial to the superior turbinate as reported by medial wall of the sinus. It usually lies halfway between the anterior Millar and Orlandi, and consistently observed by this chapter’s and posterior walls of the sinus.14 It is located in the superior authors. Although some previous observations reported it to be third of the infundibulum in 10%, the middle third in 25%, and lateral to the posterior end of the superior turbinate in 17% of the inferior third in 65% of cases.15 The natural ostium is elliptically cases,16 this may have been due to the stripping of the superior shaped; accessory ostia are round and are present in the fontanelles turbinate mucosa before measurements were taken. The sphenoid in at least 10% of patients.14 The lateral nasal wall has two areas ostium is located approximately halfway to two-thirds up the where bone is absent between the mucosa, called fontanelles. One anterior wall of the sinus and is always lower than the level of the fontanelle is anterior to the uncinate bone (anterior fontanelle) and maxillary roof. Following this endoscopic landmark, one can avoid the other is posterior (posterior fontanelle). Accessory ostia may inadvertent skull base penetration. The ostium has been described occur in these areas of weakness (either in the anterior or posterior to lie at a distance of 6.2 to 8.0 cm (average 7.1 cm) from the fontanelle) and must not be confused with the natural ostium, nasal spine at an angle of 30 to 34 degrees with the floor (see Fig. because the maxillary sinus mucus flow is always toward the natural 44.8).16-19 However, these distances can vary in patients and the maxillary ostium. It is most critical to understand that as the surgeon must identify the natural ostium endoscopically to safely Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 682 PART IV Sinus, Rhinology, and Allergy/Immunology SB PE LP ST LP Septum ST SER SM MT, v SO MT, h MT, h A B Fig. 44.7 (A) The left superior meatus (SM) has been exposed by dissecting through the oblique basal lamella of the middle turbinate (suction tip). The boundaries of the posterior ethmoidectomy are the superior turbinate (ST) medially, lamina papyracea (LP) laterally, skull base (SB) superiorly, and horizontal attachment of the middle turbinate (MT,h) inferiorly. (B) The sphenoid ostium (SO) drains into the sphenoethmoidal recess (SER) medial to the inferior third of the superior turbinate. The sphenoid ostium is usually located at the junction of the upper one-third and lower two-thirds on the sphenoid face, about 1.5 cm superior to the choana. LP, lamina papyracea; MT,v, middle turbinate, vertical part; MT,h, middle turbinate, horizontal part; PE, posterior ethmoidal cells. 30° SSS SS, LR 7 cm 9 cm ICA A B Fig. 44.8 (A) The sphenoid ostium lies at a distance of 6.2 to 8.0 cm (average, 7.1 cm) from the nasal spine, at an angle of 30 to 34 degrees to the floor. (B) The sphenoid sinus (SS) has variable pneumatization and septations (SSS). Extensive lateral pneumatization creates a lateral recess (LR). The intersinus septae (SSS) divide the sphenoid sinus asymmetrically and commonly attach to the bony canal of the internal carotid artery (ICA). enter this sinus. The visualization of the lower half of the superior turbinate, staying surgically below the level of the maxillary sinus Frontal Sinus roof and just over the top of the horizontal basal lamella, is the The frontal sinus originates embryologically from an anterior most consistent endoscopic landmark for finding the sphenoid ethmoidal cell. The connection between the frontal sinus and ostium. The sphenoid is surrounded by several critical structures anterior ethmoidal complex is not a tube or duct but an hourglass- such as the ICA, the optic nerve, and the skull base. Septations shaped space or recess. The narrowest part of this has been in the sphenoid frequently have attachments to the ICA, and if conventionally called the “frontal ostium,” although this is truly required, these septations must be removed carefully without any not an ostium (Fig. 44.9).20-24 The term “frontal opening” has torsion to avoid injury to the artery. been recently proposed as a more accurate substitute for “frontal Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 683 SB FSO 44 FS BL FSR Anterior NB Posterior BE ANC A Anterior Frontal bulla cells Posterior Suprabullar cell Frontoethmoid cells Bulla ethmoidalis Agger nasi cells B Fig. 44.9 (A) The frontal sinus recess (FSR) is an hourglass-shaped space (shaded area) with the waist at the frontal sinus ostium (FSO), which is its narrowest part. In the simplest configuration, the boundaries of the frontal recess are limited by the agger nasi cell (ANC) and nasal beak (NB) anteriorly, the bulla ethmoidalis (BE) and the bulla lamella (BL) posteriorly, the anterior skull base (SB) posterosuperiorly, the cribriform plate and middle turbinate medially, and the lamina papyracea laterally. FS, frontal sinus. (B) Frontoethmoidal cells pneumatize around the frontal recess. Frontal cells lie anterior to the frontal recess; suprabullar, supraorbital ethmoidal, and frontobullar cells lie posterior to the frontal recess. ostium,” as the sinus does not have a true two-dimensional opening, but a continuous three-dimensional space that opens into the BOX 44.1 Frontal Recess Cells20,23 frontal recess inferiorly (see Fig. 44.3). The frontal sinus drains through the frontal recess into the middle meatus (commonly) or Frontal cells: Lie above the agger nasi and pneumatize anterior to into the superior aspect of the infundibulum (less commonly; see the frontal sinus and recess (see Figs. 44.10 and 44.11). The Fig. 44.2). Messerklinger4 described frontal sinus mucociliary flow name in brackets notes the International Frontal Sinus Anatomy in 1955: mucus flows up the intersinus septum across the frontal Classification. sinus roof laterally, then medially along the floor to the frontal Type 1: A single cell superior to the agger nasi cell [agger sinus ostium, and down into the frontal recess. An estimated 40% nasi cell] to 60% of this mucus flows back up the medial frontal recess wall Type 2: A tier of two or more cells above the agger nasi cell to the intersinus septum and then recirculates up the intersinus [supra agger cell] septum to the roof. Consequently, drilling a hole in the intersinus Type 3: A single cell that extends from the agger nasi cell into septum or removing the lower part of it may not always be helpful. the frontal sinus, above the floor of the frontal sinus floor but less The terms “frontal recess” and “frontal sinus drainage pathway” than 50% of the frontal sinus height [supra agger frontal cell] refer to two separate anatomic entities. The frontal recess is the Type 4: An isolated cell within the frontal sinus (Kuhn) or a inferior part of the frontal sinus drainage pathway and lies inferior single cell that extends into the frontal sinus for greater than 50% to the frontal ostium. The medial wall of the frontal recess is of the frontal sinus height (Wormald) [supra agger frontal cell] made by the most anterior part of the middle turbinate and its Supraorbital ethmoidal cell (see Fig. 44.10): Cells posterior to lateral wall is the lamina papyracea. In the simplest pattern of the frontal sinus, pneumatizing superior to the orbital roof pneumatization, the anterior boundary of the frontal recess is Interfrontal sinus cell (see Fig. 44.10): Pneumatizes intersinus the posterior wall of the ANC, and the posterior boundary septum and drains into one frontal sinus, medial to the frontal is the ethmoidal bulla and the bulla lamella (see Fig. 44.9). The ostium [frontal septal cell] frontal sinus drainage pathway is frequently filled with various Suprabullar cell (see Fig. 44.9B): Cell superior to the ethmoidal anterior ethmoidal cells, called frontal recess cells, which consequently bulla [suprabullar cell] narrow it. Frontal bulla cell (see Fig. 44.9B): Cell superior to the Kuhn20 identified the common frontoethmoidal cells that ethmoidal bulla pneumatizing into the posterior frontal table pneumatize around the frontal recess (Box 44.1, Fig. 44.10; see (anterior skull base) [suprabullar frontal cell] also Fig. 44.9). Frontal cells lie anterior to the frontal recess, and Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 684 PART IV Sinus, Rhinology, and Allergy/Immunology Intersinus septal cell Type 4 cell Type 3 cell Frontal septal cell Supra agger frontal cell Supra agger frontal cell Type 1 cell Type 2 cell Supra agger cells Supra agger cells Agger nasi cells Agger nasi cell A B Frontal sinus Frontal bulla cells Suprabullar frontal cells Suprabullar cells Supra Frontoethmoidal cells agger frontal cells Suprabullar cell Bulla ethmoidalis Supra agger cells Bulla ethmoidalis Agger nasi cells Agger nasi cells C D Fig. 44.10 Frontal cells are of four types, depicted here on a skull model (see Box 44.1 for details). (A, C) Kuhn nomenclature20; (B, D) Corresponding new nomenclature according the International Frontal Sinus Anatomy Classification.23 the suprabullar, SOE, and frontobullar cells lie posterior to the cells are depicted in Fig. 44.10. The frontal recess anatomy must frontal recess (see Fig. 44.9). The narrow convoluted drainage be studied in axial, coronal, and parasagittal views to construct a pathway out of the frontal sinus may easily be subject to obstruc- mental three-dimensional impression of the frontal sinus drainage tion by relatively minor swelling. A complex pattern of crowded pathway and account for these cells.22-24 On a coronal CT, the frontal frontal pneumatization can cause additional problems with frontal sinus appears to be septated when SOE cells are present. Study sinus drainage.20-24 of the CT scan in axial, coronal, and sagittal reconstructions will show that the lateral “frontal sinus cell” actually lies posterior to the frontal sinus and drains via a separate opening into the frontal Importance of Frontoethmoidal Cells recess, posterior and lateral to the true frontal ostium. SOE cells Although Kuhn20 described the type 4 cell as a single isolated cell must be recognized to avoid missing the cell altogether or mistaking within the frontal sinus with no apparent connection to the frontal it for the true frontal sinus. Scarring may obstruct drainage of both recess, with modern imaging techniques that afford parasagittal the SOE and the frontal sinus due to not removing the partition sections, most type 4 cells are found to drain into the frontal that separates the SOE from the frontal sinus high enough to recess area. Wormald21 has, therefore, suggested a modification make a large common drainage chamber (Fig. 44.11). The anterior in the Kuhn classification, defining a type 4 cell as one that extends ethmoidal artery is usually not present in the partition between the into the frontal sinus for greater than 50% of the frontal sinus frontal sinus and the most anterior supraorbital cell, but running height and a type 3 cell as one that pneumatizes less than 50% obliquely through a space behind that partition in the area of the of the height. Whereas most of these cells can be reached endoscopi- bulla lamella. Dissection in this area must be done carefully to cally, some, such as high type 4 cells, may require the addition of avoid injury to the anterior ethmoidal artery, which commonly is anterior frontal sinus trephination. A recent international consensus located in or below the skull base near the attachment of the bulla document was published in 2016 in an attempt to further simplify lamella. A pedicled ethmoidal artery is usually associated with the the classification of these cells.22 The cells that lie anterior to the presence of hyperpneumatized ethmoidal cells.25 frontal sinus drainage pathway are the ANC, the supra agger cells (Kuhn type 1 and Kuhn type 2 cells) and the supra agger frontal cells (Kuhn type 3 or Kuhn type 4 cells).20-22 Anterior Skull Base Cells behind the frontal recess are the ethmoidal bulla and The anterior skull base is formed by the cribriform plate medially suprabullar and frontal bullar (supra bullar frontal cell). These and the ethmoidal roof laterally. The term “fovea ethmoidalis” is Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 685 44 SOE SOE SOE FS FS FS FS SOE SOE Fig. 44.11 Supraorbital ethmoidal (SOE) cells pneumatize over the orbital roof, posterior and lateral to the frontal sinus (FS), shown here in coronal and axial computed tomography scans and in an axial skull model on the left side. The corresponding images on the left side visualized with a 70-degree endoscope. occasionally used to refer to the ethmoidal roof, but is a misnomer injury is rare. If traumatized, these vessels should be cauterized as this area has no “fovea.” The cribriform plate has a medial part with a bipolar cautery device to avoid intracranial or intraorbital and a lateral lamella. The ethmoidal roof is much thicker than retraction and bleeding. The use of monopolar cautery or injudi- the cribriform area and extends laterally from the lateral lamella cious cauterization may also cause injury to the skull base and of the cribriform plate to the orbit, forming the roof of the create a cerebrospinal fluid (CSF) leak. ethmoidal sinuses. The cribriform plate may be only 0.1 to 0.2 mm thick and may lie much lower than the ethmoidal roof. Keros26 classified the skull base into three types, according to the depth Anatomic Variations (shallow, medium, or deep) of the olfactory groove: type 1 is 1 to Anatomic variations include structures such as a concha bullosa, 3 mm, type 2 is 4 to 7 mm, and type 3 is 8 to 16 mm. Because the ANCs, infraorbital (Haller) cells, sphenoethmoidal (Onodi) cells, very thin lateral lamella forms most of the steeply inclined ethmoidal and paradoxical middle turbinates. Concha bullosa is the term used roof in a type 3 configuration, patients with this configuration for an aerated middle turbinate or a cell found within the middle are especially vulnerable to penetration of the anterior skull base turbinate. These structures appear as a widened area of the middle during ESS (Fig. 44.12A). The cribriform area can also have turbinate, and they may obstruct the OMC. In the absence of a asymmetric heights on either side of the nose. A recent study history of rhinosinusitis, the incidental finding of a widened middle utilizes the ratio of posterior ethmoidal cell height to the maxillary turbinate during endoscopy or a concha bullosa on CT does not sinus height for assessing the height of the posterior ethmoidal mandate further investigation.29 Most patients with such variations skull base.19 If the maxillary sinus is high, the posterior ethmoid remain asymptomatic. In a review of 172 coronal sinus CT scans, is lower and suggests a lower-lying skull base. The anterior skull a concha bullosa was found in 28% of patients with sinus disease base is the highest anteriorly and slopes downward posteriorly,27 and in 26% of patients without.29 Middle turbinate pneumatization a fact that becomes important during ethmoidectomy and trans- may be in just the vertical portion, which is difficult to resect. A ethmoidal sphenoid sinusotomy. The surgeon should dissect low pneumatized uncinate is rare but can contribute to OMC obstruc- through the ethmoids until the skull base is identified. The eth- tion. Pneumatized inferior and superior turbinate concha bullosa moidal partitions are then removed from the skull base in a posterior are also rare and have unknown clinical significance. However, to anterior direction, pulling forward away from the skull base recognition of these rare patterns is important during surgical rather than pushing back into it. Before the skull base has been resection to avoid confusion (Fig. 44.13). formally identified, staying below the level of the maxillary roof can help avoid inadvertent penetration of the skull base in the posterior ethmoidal cells and sphenoid sinus.28 The anterior INDICATIONS FOR PRIMARY SINUS SURGERY ethmoidal artery lies posterior to the frontal recess, usually behind There is no absolute indication for ESS for any inflammatory, the most superior anterior ethmoidal cell. In most cases, these uncomplicated sinonasal disease. In contrast, surgery may be vessels are enclosed in the skull base and are not visible, but mandated in certain sinonasal conditions such as impending sometimes, they can lie pedicled or slinging downward within a orbital or intracranial complications, invasive fungal rhinosinusitis mesentery within the ethmoidal space.25 Preoperative survey of (IFRS), CSF rhinorrhea, sinonasal tumors, and expansile mucoceles the coronal CT scan can identify low-lying ethmoidal arteries. and polyps that cause orbital or skull base erosion. There is no The posterior ethmoidal artery can be identified in the skull base absolute contraindication to the endoscopic approach, although just anterior to the sphenoid sinus. It is important to not transect the decision to use an external or an endoscopic approach depends the ethmoidal arteries to prevent their retraction into the orbit, on the exposure needed, availability of instruments, as well as the which could cause formation of an acute orbital hematoma and surgeon’s training and experience. In the contemporary era, primary result in blindness (see Fig. 44.12B), although fortunately, such sinus surgery is almost exclusively performed endoscopically, with Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 686 PART IV Sinus, Rhinology, and Allergy/Immunology A Frontal sinus PEA SB AEA AEA B Fig. 44.12 (A) Dissection should be avoided along the medial aspect of the middle turbinate, because the roof of the ethmoid may lie higher than the cribriform plate. Left, Shallow cribriform–fovea ethmoidalis complex. Right, Low-lying cribriform plate with long lateral lamella. Instrument points to the most common area of iatrogenic cerebrospinal fluid leak. (B) The location of the ethmoidal arteries must be determined prior to skull base (SB) dissection. On a computed tomography scan, these arteries appear as conical projections from the orbit and may sometimes lie within the ethmoidal space, pedicled (outside the SB). The anterior ethmoidal artery (AEA) is located in the skull base just posterior to the frontal sinus recess. The posterior ethmoidal artery (PEA) is located just anterior to the sphenoid in the larger-appearing posterior ethmoidal cells. BOX 44.2 Indications for Primary Sinonasal Surgery U ST INFLAMMATORY SINONASAL DISEASE Chronic rhinosinusitis (with or without nasal polyposis) Recurrent acute rhinosinusitis Complications of rhinosinusitis Antrochoanal polyps MT IT Noninvasive fungal ball and eosinophilic fungal rhinosinusitis Invasive fungal rhinosinusitis Mucoceles Silent sinus syndrome OTHER Fig. 44.13 Pneumatization may involve the middle turbinate (MT), and in rarer instances, the inferior turbinate (IT), superior turbinate Intractable epistaxis (ST), and uncinate (U) bone are involved. Cerebrospinal fluid rhinorrhea and anterior meningoencephaloceles Foreign body removal Choanal atresia repair external or headlamp-guided procedures being rarely used. Box Headaches and facial pain 44.2 lists the sinonasal disease processes for which surgery may Sinonasal tumors be indicated. Expanded transnasal approaches to the skull base and orbit Chronic Rhinosinusitis CRS that is recalcitrant to medical therapy is the most common indication for surgery.30 Surgery is indicated in symptomatic care utilization for CRS, a costly disease31,32 (see Chapter 43). patients in whom appropriate medical therapy has failed. Surgery Recent studies have investigated the efficacy of continued medical is adjunctive to medical therapy. Especially in CRS with nasal therapy versus early surgery in patients with CRS.33,34 Recent polyps (CRSwNP), long-term maintenance medical therapy and studies from the United Kingdom show that delay in surgery may intermittent escalated therapy may be necessary despite surgery impact sinonasal outcomes and asthma prevalence adversely.35,36 to control disease and symptoms.30 However, ESS is effective in Surgery for CRS without nasal polyps (CRSsNP) is directed to symptom-control, disease control, as well as in decreasing health relieving obstruction in the OMC, thus improving drainage and Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 687 ventilation in the sinuses with a goal to restore mucociliary function. during an endoscopic exposure. However, with experience, ESS Surgery may be curative in some forms of CRSsNP such as is safe and effective in managing such situations.48 44 odontogenic sinusitis.30 CRSwNP is not necessarily secondary to ostiomeatal obstruc- tion, and is often driven by eosinophilic inflammation in the United Mucoceles States.37 CRSwNP may be recalcitrant to medical therapy as well Mucoceles are epithelial-lined, mucus-containing sacs that com- as surgery. In these patients, the goal of surgery is to remove pletely fill a paranasal sinus.49 They are expansile and cause bony polyps and associated debris and mucin but following the funda- erosion; therefore, they must be removed or drained to prevent mental principles of ESS (mucosal preservation and function intracranial and orbital complications. Mucoceles are more com- restoration). For these patients, a critical role of surgery is provision monly found in the frontal and ethmoidal sinuses, although isolated of wide passages for not only sinus ventilation and drainage but sphenoid mucoceles have been reported.50 In the past, open the delivery of topical medical therapy and office-based debride- approaches have been used to completely remove the lining of ments.38,39 Most critical to this is a thorough and complete eth- the mucocele. However, this practice can be dangerous, because moidectomy.40 Studies show that ESS is necessary to deliver topical mucoceles can erode through the skull base or through the lamina medical therapy as there is virtually no penetration of topical nasal papyracea into the orbit. Endoscopic management with marsupi- agents into unoperated sinus cavities.41 CRSwNP are commonly alization is preferable and safer, because complete removal of the diagnosed in association with asthma, allergic fungal rhinosinusitis cyst lining is not required. Although technically more challenging, (AFRS), and aspirin-exacerbated respiratory disease (or the Samter this latter approach is very effective, with low recurrence rates.50 triad: nasal polyps, asthma, and aspirin sensitivity); these disease The surgical goal in treatment of a mucocele is to widely open entities can be recalcitrant and very difficult to treat and impact it to allow for drainage (marsupialization) in a safe fashion, bearing outcomes.42-44 A detailed description of the pathophysiology of in mind that mucoceles often cause skull base or orbital dehiscences. CRS is beyond the scope of this chapter. However, a thorough Care must be taken to prevent scarring to avoid recurrence. The understanding of the pathophysiology is key to treating CRS; use of intraoperative image-guided navigation systems may help surgery should be personalized to address both patient symptoms in identifying and safely opening mucoceles. and the disease subtype30 (see Chapter 41). Intractable Epistaxis Antrochoanal Polyps Uncontrolled posterior epistaxis can be controlled with endoscopic An antrochoanal polyp arises from the maxillary antrum and extends assistance in identification of the bleeding vessel; this subject is posteriorly to the choana, usually through the posterior fontanelle, described in Chapter 47. and causes nasal obstruction.45 This is a relative indication for surgery. Antrochoanal polyps are solitary, unilateral lesions that Cerebrospinal Fluid Rhinorrhea and arise from the maxillary sinus and grow toward the choana. They must be differentiated by imaging or biopsy characteristics from Anterior Meningoencephaloceles neoplastic processes prior to undertaking “polypectomy.” If removed Endoscopic repair is now a standard approach for repair in cases completely along with the antral part, these polyps are unlikely of CSF rhinorrhea and meningoencephaloceles, with success rates to recur. A supplementary sublabial, transcanine, or inferior meatus higher than 90%. CSF rhinorrhea and meningoencephaloceles approach may be necessary in some patients. The traditional are both described in detail in Chapter 48. Caldwell-Luc surgery is not necessary (i.e., stripping of the maxillary sinus mucosa) for these polyps. The creation of a small, temporary endoscopic inferior meatal antrostomy for endoscopy or instru- Noninvasive Fungal Rhinosinusitis mentation can improve access to the polyp and will usually scar Noninvasive fungal sinusitis includes “fungal ball” and “allergic down. Extension of the middle meatal antrostomy to the floor of fungal sinusitis.”51 Fungus balls can occur in any paranasal sinus. the nasal cavity by resecting the midsegment of the inferior The treatment is removal of the debris by ESS. A large antrostomy turbinate (mega-antrostomy) may be another option. Endoscopes or ostioplasty is created, and fungal debris is irrigated and removed. and curved powered or grasping instruments are very helpful in Usually, no further medical therapy is required. The presence of the removal of the maxillary portion of the polyp, which is the associated sclerotic and osteolytic changes in the affected sinus key to avoiding failure. should alert the physician to the chronicity of this pathology. Patients with dense osteitic changes in the sinuses, especially in hypoplastic sphenoid sinus often show tendency for stenosis of Recurrent Acute Rhinosinusitis the surgical neo-ostium.51 Surgery may be indicated for patients with recurrent acute rhi- nosinusitis, defined as four or more clinical episodes annually.46 Disease should be confirmed by means of at least one objective Allergic Fungal Rhinosinusitis criterion (endoscopically or on CT scan) while the patient is AFRS is usually treated with a combination of ESS, medical therapy, symptomatic. A positive CT scan or nasal endoscopy at the time and immunotherapy.30 Patients with histopathologic evidence of of infection should be ascertained before any surgical intervention AFRS without elevated immunoglobulin E (IgE) to fungus are is undertaken. Many noninflammatory disorders such as migraines classified as having nonallergic fungal rhinosinusitis (NAEFRS).52 and other headache disorders can be frequently present with a Clinically, patients with AFRS are atopic, and may have nasal heavy burden of sinonasal symptoms and can be misdiagnosed as polyps and comorbid asthma.30 Surgical management specific to recurrent acute rhinosinusitis.47 AFRS is detailed later in the chapter under the section of surgery for CRSwNP. Acute Complications of Rhinosinusitis Acute complications, both orbital and intracranial, that are Invasive Fungal Rhinosinusitis unresponsive to medical therapy require immediate surgical IFRS is almost exclusively a disease of the severely immuno- intervention. External procedures have been used in the past, compromised. All avascular and necrotic tissue must be debrided because nasal edema and inflammation can compromise visualization until healthy, bleeding tissue is encountered. Serial debridements Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 688 PART IV Sinus, Rhinology, and Allergy/Immunology may be necessary every 2 to 3 days, and the disease is kept under turbinate operation should be used only if relief from medications stringent surveillance by serial endoscopy and radiographic imaging. point to a specific anatomic problem, or if specific physical or An open approach can be combined in extensive disease or with radiographic data indicate a problem site. Even with these pre- involvement of the skin, subcutaneous tissue, or bone (nasal, requisites, surgery has variable results, may be unsuccessful, and palatine, and maxillary). The prognosis remains grim in spite of may worsen the headache. Long-term results may be poor, and a optimal debridement by any approach, because patients have follow-up of at least 1 year is necessary to confirm a successful multisystemic comorbidities.52 Therapy for IFRS requires reversal outcome.60 of the underlying predisposing condition, systemic antifungal therapy (initial broad spectrum followed by culture-directed antifungals), and surgical debridement. Ability to reverse underlying Silent Sinus Syndrome immunodeficiency is critical to survival.53 If the immunocompromised The etiology of silent sinus syndrome (SSS) is unclear. SSS is status is profound and irreversible, any surgical treatment is unlikely associated with obstruction of the OMC. The resultant negative to be successful; in these patient subsets, mutilating and painful pressure is presumed to cause a gradual implosion of the maxillary therapy should be avoided. IFRS in the immunocompetent patient cavity, resulting in a very small and contracted maxillary sinus. is rare, and the course is generally chronic, although it may still The uncinate process is lateralized toward the maxillary sinus, be lethal. Chronic IFRS includes both granulomatous and non- getting plastered to the medial orbital wall. The roof of the granulomatous subtypes, and surgical management is similar in sinus, which is the orbital floor, may also be “sucked” toward philosophy to treatment for acute FRS. the maxillary sinus and may cause enophthalmos. Mucus and secretions collect within the sinus, and a simple uncinectomy and maxillary antrostomy are effective for treating this condition Removal of Foreign Bodies and for preventing further enophthalmos. Great care is necessary Endoscopy is helpful in the visualization of foreign bodies and when removing the uncinate process plastered against the orbit aids in their atraumatic removal. to avoid orbital injury.61 Choanal Atresia Repair Tumors and Expanded Utilization of Transnasal Endonasal endoscopic approaches can be used in lieu of transpalatal Endoscopic Sinus Approaches approaches to treat both unilateral and bilateral choanal atresia Unilateral nasal masses should be thoughtfully evaluated. Benign in suitable cases.54 and malignant tumors of the nasal and paranasal cavities may be resected endoscopically or with endoscopy-assisted approaches.62-64 However, it is important not to perform “debulking” proce- Headache and Facial Pain dures for sinonasal tumors, as they may impact prognosis for The role of surgery for treatment of headaches is very controversial. patients. Instead, tumors should be removed following oncologic ESS may offer benefit in a very limited number of patients who principles carefully, by identifying and widely resecting sites of have headache and facial pain, and surgery on such patients must attachment.61-63 Oncologic margins should be taken where feasible. be undertaken after a thorough neurologic evaluation. Lal et al. The most common sinonasal tumor that is addressed surgically reported that multidisciplinary care with otolaryngologists and is sinonasal inverted papilloma.62,63 The advent of endoscopic neurologists may offer patients presenting with sinus headache techniques, as well as the use of frozen section histopathology and pain the most successful outcomes.55 Patel et al.56 have proposed and margins, may decrease recurrence rates for these tumors.62,63 an algorithm for diagnosing and managing sinus headaches, dif- Select orbital and cranial base pathology can also be addressed ferentiating between rhinogenic and neurologic causes. A stable endoscopically.65-68 pattern of recurrent headaches with headache as the presenting complaint is most likely migraine.57 Recurrent self-limited headaches associated with rhinogenic symptoms are also most likely migraine.56 ENDOSCOPIC SINUS SURGERY FOR RHINOSINUSITIS Prominent rhinogenic symptoms with headache as one of several complaints should be evaluated for otolaryngologic pathology.55-57 Principles of Functional Endoscopic Sinus Surgery Headache with associated fever and purulent nasal discharge may The primary objective of functional endoscopic sinus surgery be rhinogenic in origin and is best assessed by nasal endoscopy (FESS) is to restore paranasal sinus function by reestablishing and sinus CT.54,55-57 For patients with normal CT findings and no the physiologic pattern of ventilation and mucociliary clearance. rhinogenic cause of headache, the role of sinus surgery is debated. Normal mucociliary transport is necessary to maintain ostiomeatal According to Parsons and Batra58 and Clerico and associates,59 patency.68 The cilia of the maxillary and frontal sinuses transport the finding of contact points on CT and/or endoscopy is a pre- mucus in specific patterns only toward the natural ostia, despite the requisite for surgery. They also emphasize that the presence of presence of accessory ostia.69 FESS is designed to alleviate OMC contact points is not pathognomonic, because many patients with obstruction. The term “full-house” FESS has become popular contact points have no headache. Clerico et al.59 state that it is recently to refer to complete sphenoethmoidectomy with Draf IIA important to “prove” the correlation of the contact point with frontal sinusotomy.70 The goal of ESS is to remove irreversibly headaches by noting the response to medical therapy or to a diseased mucosa and bone, preserve normal tissue, and judiciously diagnostic anesthetic block. Surgery should be offered only if widen the true natural ostia of the sinuses. The OMC is most often patients have a clear reduction in headache in response to intranasal the primary target of ESS, because minimal inflammation in this decongestants and anesthetic sprays or with obvious findings on area can lead to disease in the maxillary, anterior ethmoidal, and endoscopy, CT, or both. In a retrospective series of 34 patients, frontal sinuses. Bony septations should be removed, but aggressive Parsons and Batra58 reported a reduction in the intensity and removal of mucosa is inappropriate and can cause postoperative frequency of headaches (91% and 85%, respectively) in patients scarring and failure from surgery. The mucosal lining of the skull who underwent ESS to relieve the contact points identified on base, lamina papyracea, and sinus cavities should be preserved, CT. However, others are less optimistic. Stankiewicz60 and Lal and uninvolved sinuses should be left alone. A thorough eth- et al.55 state that surgery should be resorted to only after both moidectomy with complete removal of the cells is critical to not thorough neurologic and radiographic evaluation and failure of just the ethmoidectomy itself, but also for successful maxillary medical therapy. A directed, targeted endoscopic sinus, septal, or antrostomy and frontal sinusotomy. In spite of adequate surgery, Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved.  CHAPTER 44 Primary Sinus Surgery 689 mucosal disease may persist and may require further medical and TABLE 44.1 Key Factors to Be Reviewed on Preoperative Computed surgical therapy. Tomography Scan Before Endoscopic Sinus Surgery 44 Factor Details Extent of Surgery: Limited versus Disease Extent and pattern Extended Approaches Clinical correlation The extent of surgery is determined by the disease subtype and Bony integrity Skull base (erosion, expansion, Lamina papyracea patient factors. More extensive surgery may be necessary for Optic canal and dehiscence) complicated acute rhinosinusitis or for eosinophilic CRS and Carotid canal CRSwNP.30 Each patient is individually assessed to determine Skull base Height the site of pathology and obstruction, and surgery is tailored to Symmetry address these. In more limited disease, limited surgery may be Slope of cribriform plate and fovea adequate.71 ethmoidalis Maxillary/posterior ethmoid height ratio Maxillary sinus Location and attachment of uncinate Preoperative Assessment process to medial orbital wall Pneumatization and height (hypoplastic History maxillary sinus has low orbital floor) Presence of infraorbital cells Patients should generally be treated with optimal medical therapy Ethmoidal complex Location of anterior and posterior ethmoidal and fail adequate disease control to be considered candidates for arteries surgery. Factors that have been associated with poorer outcomes Height of posterior ethmoidal cells from surgery must be assessed preoperatively. These include (determines slope of the skull base) smoking, asthma, aspirin sensitivity, allergies, immunodeficiency, Large sphenoethmoidal (Onodi) cells and and depression (see Chapter 45 for details).30,44,45 their relationship to the optic nerve Sphenoid sinus Location of sphenoid ostium Sphenoid septations and relation to carotid Examination canal Frontal sinus Extent of pneumatization (deeper fovea Office examination comprises a complete head and neck examina- ethmoidalis noted on side with a frontal tion, a basic ocular examination, anterior rhinoscopy, and nasal cell and/or hyperpneumatized frontal sinus) endoscopy. Anterior rhinoscopy detects any significant septal Natural drainage pathway deviation and nasal valve collapse that may need to be addressed Presence of agger nasi/frontoethmoidal cells as well. Nasal endoscopy should be conducted in a systematic Anteroposterior diameter of frontal recess in sagittal section fashion with a rigid or flexible endoscope.30,48 The character of Miscellaneous Septal deviations and their clinical correlation the mucosa, appearance of the sinus drainage pathways, and the Concha bullosa presence of anatomic variations, structural abnormalities, purulent Abnormalities within the orbit drainage, and polyps are noted.30,48 Radiographic Assessment CT scans are performed to assess sinonasal anatomy and disease must be carefully studied to construct a three-dimensional evalu- pattern to guide surgery.30,48 If bony dehiscence or erosion of the ation of the relevant anatomy. “Screening sinus CT,” with a limited skull base or lamina papyracea is present, magnetic resonance number of coronal views, may be useful for diagnosis of sinusitis, imaging may be indicated for differentiating inflammatory sinus but coronal CT with a maximum of 5-mm slices is needed to pathology from tumors and possible encephaloceles. Noncontrast avoid loss of anatomic information for surgical planning.72 Modern CT scans72 ordered for diagnostic purposes are useful for preopera- CT scanners can perform 0.5-mm slices without prolonging tive planning and can also be used for image guidance if they scanning time. are protocoled for use in navigation systems. Blockage of any of The CT scans are carefully reviewed before surgery and the sinus drainage pathways can usually be identified from the must be available for review during the procedure to enable presence of retained fluids within the sinuses. The cause of the evaluation of the extent of disease and to assist with operative blockage can also frequently be determined from the presence of planning. A mental or formal checklist is useful for preoperative thickened mucosa, polyps, or anatomic abnormalities. Mineraliza- planning (Table 44.1). Meyers and Valvassori27 reviewed 400 tion or hyperintense signals can be evidence of fungus or tumors. preoperative CT scans with attention to anatomic variations. Care must be exercised in interpreting “positive” CT findings They found six specific variations that may predispose a surgeon by correlating them with the patient’s symptoms.73-75 Incidental to inadvertent penetration of the orbit or the anterior cranial sinus opacifications can be found on up to 27% of sinus CT cavity. These variations are: (1) a lamina papyracea lying medial scans.74 Patients with CRS with positive endoscopy should be to the maxillary ostium; (2) maxillary sinus hypoplasia; (3) fovea treated medically, and the sinus CT obtained 3 to 4 weeks after ethmoidalis abnormalities, such as a low or sloping fovea; (4) therapy is used to evaluate the effect of treatment.76 If the CT lamina papyracea dehiscence; (5) sphenoid sinus wall variations, scan then reveals evidence of persistent inflammation, surgery may such as septa attached to the carotid or dehiscence of the carotid be indicated. Upfront CT scans can be considered in symptom- or optic nerve; and (6) SECs. Hyperpneumatization of the frontal atic patients with negative endoscopy to determine subsequent sinus or presence of a frontal cell may be associated with a deep management.77 fovea ethmoidalis.25,27 Coronal views show the ostiomeatal unit and the relationship of the brain and orbit with the paranasal sinuses. Axial CT views complement coronal views and must be obtained for the planning Intraoperative and Perioperative Considerations of surgery for severe disease in the posterior ethmoidal and sphenoid Instrumentation for ESS includes an array of endoscopes (0, 30, sinuses. Sagittal views are particularly useful in evaluating frontal 45, and 70 degrees). Reverse-angled scopes are now available, recess anatomy and the slope of the skull base. All three planes where the post is situated on the same side as the lens. This creates Downloaded for Jameel Ghantous ([email protected]) at Shaare Zedek Medical Center from ClinicalKey.com by Elsevier on November 28, 2020. For personal use only. No other uses without permission. Copyright ©2020. Elsevier Inc. All rights reserved. 690 PART IV Sinus, Rhinology, and Allergy/Immunology more room under the endoscope to pass instruments and is especially useful in endoscopic skull base surgery, where two surgeons operate at the same time. An appropriate set of straight and angled instruments to approach all sinuses should be available. Powered instrumentations such as shavers (microdebriders) are very useful in patients with polyps, and they also help create sharp mucosal edges. A suction trap attached to the microdebrider may be used to collect tissue for histopathology. A structured histopathol- ogy report may be critical to fabricating postoperative medical management and for prognostication.78,79 The use of an Endo-Scrub flushing system (Medtronic, Minneapolis, MN) is helpful in procedures that are anticipated to be bloody. Both permanent and disposable sheaths that fit onto various angled endoscopes are now available. The image guidance system is optional for use where indicated. The choice of anesthesia, perioperative medical therapy, and postoperative care must be planned in advance of surgery. Interven- tions to optimize the surgical field and postoperative outcomes must be determined. Bleeding in the surgical field makes visualiza- Fig. 44.14 Image-guided navigation systems use reformatted thin-cut tion and identification of landmarks difficult and may also prolong computed tomography scans in coronal (top left), sagittal (top right), operative time, increase risks of complications, and create difficulty and axial section (bottom left) to create a three-dimensional view that in completing the planned surgery. Many interventions have is correlated intraoperatively with actual patient anatomy as seen been proposed to optimize hemostasis and the field of view. through the endoscope (bottom right). These include use of the reverse Trendelenburg position and administration of topical vasoconstrictors and favorable anesthetic techniques.80-84 operative time and cost. Depending on the system used and the Preoperative Medical Therapy medical facility charges, operating time and hospital cost may be Antibiotics and oral steroids may be started 7 to 10 days before significantly higher with the use of a navigation system.87,88 As the surgery to reduce severe inflammation from purulent CRS.84,85 use of image guidance systems becomes more popular, the question Preoperative oral corticosteroid therapy in patients with reactive arises as to whether this is now a standard of care or still state-of lower airway disease may enhance surgical safety and prevent the-art technology,89 and whether outcomes are improved with respiratory complications. Perioperative oral corticosteroid therapy the use of these navigation systems.90-92 In a comparison of 60 may be beneficial in improving the operative field and postoperative patients undergoing image-guided surgery (IGS) and 179 patients healing in CRSwNP patients.86 Research is needed to evaluate undergoing ESS without image guidance, Tabaee and colleagues90 the efficacy of systemic steroids for patients with CRSsNP in the found no statistically significant difference in the incidence of perioperative period.86 major intraoperative or postoperative complications, the number of revision procedures, and postoperative SNOT-20 symptom scores.90 However, a higher incidence of intraoperative CSF leak Intraoperative Considerations was noted in the group undergoing surgery without image guidance—2.2% versus 0% in the IGS group. Analysis of 355 Image-Guided Navigation Systems surgeries performed at a single institution in 2013 showed that An inherent problem with endoscopic surgery is the two- the use of intraoperative image guidance did not reduce risk of dimensional view afforded by the use of the single lens. Navigational complications, but it may have been helpful in reducing revision systems were developed to help reduce the risks of ESS. These surgeries.91 However, in the same year, Dalgorf and colleagues92 systems use thin-cut CT scans reformatted in various planes to performed a systematic review and meta-analysis of the literature create a three-dimensional configuration. This three-dimensional and came to a different conclusion. The authors reviewed 2586 view is then correlated with actual patient anatomy intraoperatively articles and studied 55 articles for further analysis, of which 14 with the help of a computer (Fig. 44.14). The surgeon can place comparative cohorts of image-guided sinus surgery (IGS) and a probe on any structure to get a real-time, three-dimensional non-IGS sinus surgery populations were used for meta-analysis. view of the position of the probe. These computer-assisted naviga- Major complications were more common in the non-IGS group tion systems, which can be extremely helpful for difficult cases (RR = 0.48; 95% confidence interval [CI], 0.28 to 0.82; P =.007). and for revision surgery, are becoming increasingly popular. Early Total complications were greater in the non-IGS group (RR = reports showed that this technology was rapidly embraced.87 0.66; 95% CI, 0.47 to 0.94; P =.02). All other outcomes did not However, navigation systems are aids to the endoscopic sinus reach significance on meta-analysis.92 surgeon; they are not a substitute for a thorough understanding As the risk of major complication in the contemporary era is of the surgical anatomy. Even under ideal circumstances, they are relatively low, a very large population-based study may be neces- associated with some degree of inaccuracy or error.87,88 Accuracy sary to show any positive benefits from the use of navigation to within 2 to 3 mm is acceptable for image guidance systems, systems. The American